Work chairs often position workers in a posture where the worker slouches in his or her chair. The slouched posture causes the spine of the worker to be in a rounded condition known as kyphosis. A sitting posture that causes kyphosis of the spine is damaging to the back because the spinal column is displaced from its normal curvature. When the seated person maintains the normal curvature of the back, known as lordosis, little or no strain is place on the discs of the spinal column or on the soft tissue adjacent to the spine. When the seated person slouches forward causing the back to be rounded, the discs are stressed at their forward edges. Additionally, the muscles and the other soft tissue adjacent to the spinal column must stretch excessively to accommodate the rounding of the back.
Office work using a computer, microscope, or drafting table often requires a static posture for long periods of time. Workers maintaining a poor sitting posture for long periods often may cause static stress injuries to the discs of the spinal column or to the adjacent soft tissue. For workers with back injuries, a poor seated posture causing kyphosis of the spinal column can inflame the previously damaged tissue resulting in considerable discomfort.
As the understanding of work related injuries has increased, attempts have been made to improve the postures of seated workers. The typical solution suggested to workers to improve their posture is to use an independent, floor supported foot rest to raise their feet above the floor. Once the feet are raised, the user can more easily sit upright in a sitting posture that restores lordosis to the spine.
While these foot rests are somewhat successful in improving the posture of the worker seated at a work chair there are deficiencies with the use of foot rests of this type. A first deficiency results from the foot rest existing independent of the chair. This feature results in the foot rest often being located away from where it is convenient to reach and consequently the foot rest is unused. Several foot rests of this type would be needed to correspond to the various work locations within a modern office where a worker may be required to work during a normal work day.
Another problem with foot rests of this type is due to the inability to adjust the height of the foot rest to accommodate different chair seat heights. Modern work chairs allow the user to adjust the chair seat height to various vertical positions which help the user maintain a comfortable posture during various work tasks. A foot rest that is not able to be adjusted a corresponding amount does not allow the user to maintain the proper posture required at each chair height.
Elevated work chairs or stools have included foot rests integrally into the chair design. The foot rests used in these chairs have also had deficiencies. Foot rests for these elevated work chairs are commonly placed beneath the chair seat. In this position the legs are not forward enough for the user to easily maintain a proper posture with lordosis achieved in the spinal column. If foot rests of this type were more forward they would restrict chair maneuverability by obstructing the leg and foot area between the chair cushion and the floor.
Another problem with the foot rest mechanisms used in existing elevated chairs is the difficulty in positioning the foot rest into the desired position. The foot rest mechanisms currently in use often allow the foot rest to assume either of two positions (an in use position, and a retracted position) or are fixed into a single position. Obviously, foot rest mechanisms have not kept pace with the high degree of adjustability advanced in the design of the other chair components.
Because of the deficiencies associated with existing foot rests there is a need for a foot rest mechanism for work chairs that attaches directly to a chair where the foot rest is readily accessible and efficiently removed as an obstacle to the user's contact with the floor. There is also a need that this foot rest mechanism extends to an outward position relative to the chair seat so that proper leg extension can be achieved for proper posture. There is a further need for a foot rest mechanism that may be positioned at a variety of positions relative to the chair seat and can be repositioned with a minimum of effort. There is also a need for a foot rest mechanism of this type which can be attached to existing work chair designs including elevated stools as well as non-elevated work chairs.